1. Field of the Invention
This invention relates to prosthesis devices for replacement of segments of the ureter. More particularly, it relates to a distal ureter prosthesis which is adapted to feed directly into the bladder.
2. Prior Art
The ureter is a fibromuscular tube which conveys urine from the kidney to the bladder. It begins with the pelvis of the kidney, a funnel-like dilatation and empties into the base of the bladder. A normal length for an adult ureter is approximately 16 to 18 inches.
Numerous conditions may arise which can cause the need for replacement of all or part of the ureter. Pelvic and primary carcinoma represent major causes for uretheral blockage or failure. In addition, radiation injuries, trauma and iatrogenic injuries can develop conditions requiring replacement of the ureter.
Many attempts have been made to develop a uretheral graft useful for replacing a non-terminal segment of the ureter. Experimentally in animals, segments of ureter have been replaced by abdominal wall fascia, Fallopian tubes, polyvinyl chloride, vitalium, freeze-dried arteries and veins, tantalum, polyethylene, TEFLON, and silicone rubber. The polyethylene and silicone rubber tubes have proved to be moderately successful when used to replace segments of the dog ureter.
A much more difficult challenge arises with the replacement of a distal ureter segment which empties into the bladder. Previous attempts to develop a distal ureter with a one-way valve mechanism to prevent vesico-ureteral reflux have been prepared from TEFLON, silicone rubber and stainless steel. None of these devices, however, have met with success. Common problems which have apparently led to graft failure have included migration of the implant, leakage, stenosis at the prosthesis-uretheral or prosthesis-bladder junction and incrustation with resultant hydronephrosis. Also, a general poor tolerance of the graft material has contributed to prosthesis failure in many of these cases.